This invention relates to a new composition of matter and a method for preparing the composition and more particularly, to an ethynylene-disilanylene copolymer and a method for ethynylene-disilanylene copolymers.
Various types of organic, metal organic, and inorganic materials are known to have unusual highly anisotropic and potentially useful electric, optical, and/or magnetic properties. Such materials are known to be useful in fabricating electrically conducting materials, semi-conductors, electronic devices, and electromagnetic or acoustic sensors. The utility of some of these materials is frequently limited by such factors as weight, mechanical fragility, fabrication problems, corrosion, scarcity, and high costs.
Electroconductive organic materials have properties which can overcome or minimize such problems, and have the capability to be easily fabricated into films, filaments, and other shapes. Some of these materials are simply an organic compound containing a conductive material therein, such as a metal or graphite. Others comprise polymeric organic material whose electrical conductivities are established by chemical doping with electron acceptor and/or electron donor dopants. In general, the polymeric materials susceptible of establishing such electrical conductivity are characterized by highly delocalized .pi. electron conjugation, or by .sigma.-electron delocalization which are found in, for example polysilane materials. Polysilanes can also be used as resist materials, .beta.-SiC precursors, as well as an initiator for radical polymerization.
Electron delocalization between Si-Si .sigma. bonds and .pi. systems has been conclusively established in various polysilyl compounds containing unsaturated or aromatic groups. But examples of Si-Si .sigma.-.pi. electron delocalization in a polymer backbone have heretofore been relatively few. .sigma.-.pi. electron delocalization in such polysilyl compounds generally results in a longer wavelength shift by 20-30 nm in UV spectra relative to the absorption maximum of hexamethyldisilane which just has o-electrons. Representative values of absorption max in UV spectra of some Si-Si .sigma.-.pi. electron delocalized compounds are set forth in Table I. Compounds 2-4 of Table I, because of their strong absorption over 215 nm, should have a high degree of .sigma.-.pi. electron delocalization and, in fact, may exhibit a high potential for use as an electroconductive material.
TABLE I ______________________________________ UV Absorption Maxima of .sigma. (Si--Si)-.pi. Electron Delocalized Compounds Compound .lambda. max (nm) ______________________________________ 1. Me.sub.3 Si--SiMe.sub.3 197-200 2. PhMe.sub.2 Si--SiMe.sub.3 231 3. HC.tbd.C--SiMe.sub.2 SiMe.sub.2 --C.tbd.CH 217 4. Me.sub.3 Si--C.tbd.C--SiMe.sub.2 SiMe.sub.2 --C.tbd.C--SiMe.sub.3 223, 230 ______________________________________
Further, like other polysilanes, the copolymers of the subjection invention may undergo conversion to silicon carbide when heated to high temperatures.